If I understand the question, you want to remove a node from your Cluster and install Apache Hadoop directly.
No requirement to preserve data.
You can got to "Hosts-> All Hosts" in Cloudera Manager, select the node and from Actions menu you can do sequentially:
- Stop Roles on Hosts
- Remove from Cluster
- Remove from Cloudera Manager
Before you do the last step, stop and disable cloudera-scm-agent
# systemctl stop cloudera-scm-agent
# systemctl disable cloudera-scm-agent
Then, you can uninstall cloudera-scm-agent from this node, and install the Apache Hadoop.